From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18FACC47258 for ; Tue, 23 Jan 2024 11:44:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8EDC08D0006; Tue, 23 Jan 2024 06:44:44 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 89D728D0001; Tue, 23 Jan 2024 06:44:44 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 717408D0006; Tue, 23 Jan 2024 06:44:44 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 616658D0001 for ; Tue, 23 Jan 2024 06:44:44 -0500 (EST) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E5BBA16033D for ; Tue, 23 Jan 2024 11:44:43 +0000 (UTC) X-FDA: 81710393646.04.BB949CE Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf20.hostedemail.com (Postfix) with ESMTP id 1E5351C0005 for ; Tue, 23 Jan 2024 11:44:41 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf20.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1706010282; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5EN/2YewISdC4fhpe3FRr6pD3HZdH5q+oZRG6Ox2Bg8=; b=QzpYWm2oEF74/aaYIe24coXhZbvXfRPnqERJdlSCr7/od1+PxSRVeQYPTHNswjMjzgbKQ3 +VeDOarnBsjDB2KzsROh3gtB8zXfVdLoMMjQfRQiyJidsefzb/59BaFGkU/LgIrIHNTdeH i7rtLzL4RuPfWaWqN81iT1KEhz7Rfu0= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf20.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1706010282; a=rsa-sha256; cv=none; b=5wVNxEG6CCEYSGtudUkoWVx2XWwT1j1nnk9pSWtMYnmS61rzq+zQaTWSBRlvjpBBky9/C0 iV86rCl/L0qh9bnx+R6hUm3tVt7nRPBysRlRYug/JM1G8p+9dWhPsGEOIFIz3dNq2KwnrZ slKCjaauFFuZSE9KcwOtY32JkaPM11I= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 60D9A1FB; Tue, 23 Jan 2024 03:45:26 -0800 (PST) Received: from [10.57.77.165] (unknown [10.57.77.165]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 47CA23F762; Tue, 23 Jan 2024 03:44:37 -0800 (PST) Message-ID: <7f39e2db-0fa1-4391-956f-d2586fa234bd@arm.com> Date: Tue, 23 Jan 2024 11:44:35 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 01/11] arm/pgtable: define PFN_PTE_SHIFT on arm and arm64 Content-Language: en-GB To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Andrew Morton , Matthew Wilcox , Russell King , Catalin Marinas , Will Deacon , Dinh Nguyen , Michael Ellerman , Nicholas Piggin , Christophe Leroy , "Aneesh Kumar K.V" , "Naveen N. Rao" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , "David S. Miller" , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org References: <20240122194200.381241-1-david@redhat.com> <20240122194200.381241-2-david@redhat.com> <46080ac1-7789-499b-b7f3-0231d7bd6de7@redhat.com> <02d42161-a867-424d-bef8-efd67d592cbc@redhat.com> <75e99c49-734a-47f4-b7a5-7e346bd2487b@arm.com> <08607590-3115-46e6-8f1f-bcc60c33cc20@redhat.com> From: Ryan Roberts In-Reply-To: <08607590-3115-46e6-8f1f-bcc60c33cc20@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 1E5351C0005 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: gwr1xdm5ywyhfy1dejxnaxm7o44sbdij X-HE-Tag: 1706010281-299887 X-HE-Meta: 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 ojGgyyzU ORG48+MYAbtJ6t6gdqqY7OZ5uPxPOTzcxCPywScUCCD0+Cmz20lzvfFQol5waeIn5I3Mnh76oJPKNV0v97k61rmVYb87gKPuMzlumiIrn2nJz81XvraHCtq7JlLep44Q2KuT+8/BXuQV6bR4RaoCHN/0y97GtAPVc0TXBIyqxq7Ece1n/Dc3xM/Cnn9jy8es+jzz1/Vd0oNjRx1KCB9ATEK68WpbpeMoza89A X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 23/01/2024 11:33, David Hildenbrand wrote: > On 23.01.24 12:17, Ryan Roberts wrote: >> On 23/01/2024 11:02, David Hildenbrand wrote: >>> On 23.01.24 11:48, David Hildenbrand wrote: >>>> On 23.01.24 11:34, Ryan Roberts wrote: >>>>> On 22/01/2024 19:41, David Hildenbrand wrote: >>>>>> We want to make use of pte_next_pfn() outside of set_ptes(). Let's >>>>>> simpliy define PFN_PTE_SHIFT, required by pte_next_pfn(). >>>>>> >>>>>> Signed-off-by: David Hildenbrand >>>>>> --- >>>>>>     arch/arm/include/asm/pgtable.h   | 2 ++ >>>>>>     arch/arm64/include/asm/pgtable.h | 2 ++ >>>>>>     2 files changed, 4 insertions(+) >>>>>> >>>>>> diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h >>>>>> index d657b84b6bf70..be91e376df79e 100644 >>>>>> --- a/arch/arm/include/asm/pgtable.h >>>>>> +++ b/arch/arm/include/asm/pgtable.h >>>>>> @@ -209,6 +209,8 @@ static inline void __sync_icache_dcache(pte_t pteval) >>>>>>     extern void __sync_icache_dcache(pte_t pteval); >>>>>>     #endif >>>>>>     +#define PFN_PTE_SHIFT        PAGE_SHIFT >>>>>> + >>>>>>     void set_ptes(struct mm_struct *mm, unsigned long addr, >>>>>>                   pte_t *ptep, pte_t pteval, unsigned int nr); >>>>>>     #define set_ptes set_ptes >>>>>> diff --git a/arch/arm64/include/asm/pgtable.h >>>>>> b/arch/arm64/include/asm/pgtable.h >>>>>> index 79ce70fbb751c..d4b3bd96e3304 100644 >>>>>> --- a/arch/arm64/include/asm/pgtable.h >>>>>> +++ b/arch/arm64/include/asm/pgtable.h >>>>>> @@ -341,6 +341,8 @@ static inline void __sync_cache_and_tags(pte_t pte, >>>>>> unsigned int nr_pages) >>>>>>             mte_sync_tags(pte, nr_pages); >>>>>>     } >>>>>>     +#define PFN_PTE_SHIFT        PAGE_SHIFT >>>>> >>>>> I think this is buggy. And so is the arm64 implementation of set_ptes(). It >>>>> works fine for 48-bit output address, but for 52-bit OAs, the high bits are >>>>> not >>>>> kept contigously, so if you happen to be setting a mapping for which the >>>>> physical memory block straddles bit 48, this won't work. >>>> >>>> Right, as soon as the PTE bits are not contiguous, this stops working, >>>> just like set_ptes() would, which I used as orientation. >>>> >>>>> >>>>> Today, only the 64K base page config can support 52 bits, and for this, >>>>> OA[51:48] are stored in PTE[15:12]. But 52 bits for 4K and 16K base pages is >>>>> coming (hopefully v6.9) and in this case OA[51:50] are stored in PTE[9:8]. >>>>> Fortunately we already have helpers in arm64 to abstract this. >>>>> >>>>> So I think arm64 will want to define its own pte_next_pfn(): >>>>> >>>>> #define pte_next_pfn pte_next_pfn >>>>> static inline pte_t pte_next_pfn(pte_t pte) >>>>> { >>>>>      return pfn_pte(pte_pfn(pte) + 1, pte_pgprot(pte)); >>>>> } >>>>> >>> >>> Digging into the details, on arm64 we have: >>> >>> #define pte_pfn(pte)           (__pte_to_phys(pte) >> PAGE_SHIFT) >>> >>> and >>> >>> #define __pte_to_phys(pte)     (pte_val(pte) & PTE_ADDR_MASK) >>> >>> But that implies, that upstream the PFN is always contiguous, no? >>> >> >> >> But __pte_to_phys() and __phys_to_pte_val() depend on a Kconfig. If PA bits is >> 52, the bits are not all contiguous: >> >> #ifdef CONFIG_ARM64_PA_BITS_52 >> static inline phys_addr_t __pte_to_phys(pte_t pte) >> { >>     return (pte_val(pte) & PTE_ADDR_LOW) | >>         ((pte_val(pte) & PTE_ADDR_HIGH) << PTE_ADDR_HIGH_SHIFT); >> } >> static inline pteval_t __phys_to_pte_val(phys_addr_t phys) >> { >>     return (phys | (phys >> PTE_ADDR_HIGH_SHIFT)) & PTE_ADDR_MASK; >> } >> #else >> #define __pte_to_phys(pte)    (pte_val(pte) & PTE_ADDR_MASK) >> #define __phys_to_pte_val(phys)    (phys) >> #endif >> > > Ah, how could I've missed that. Agreed, set_ptes() and this patch are broken. > > Do you want to send a patch to implement pte_next_pfn() on arm64, and then use > pte_next_pfn() in set_ptes()? Then I can drop this patch here completely from > this series. Yes good idea. I probably won't get around to it until tomorrow.